This invention relates to electrical connectors and, more particularly, to such a connector with the ability to be retained to a circuit board during soldering and which accommodates surface mount solder joints in printed circuit board holes.
When mounting and electrically interconnecting components on a printed circuit board, two commonly used processes are wave soldering and surface mount soldering. For wave soldering, leads from the individual components are inserted into respective holes in the printed circuit board from a top surface thereof. Additionally, contacts from an electrical connector to be mounted to the board are inserted into respective holes from the top surface. A wave of molten solder is then applied to the bottom surface of the board. The solder enters the holes, filling them and making mechanical and electrical connections.
In the surface mount process, a solder paste is applied to the top surface of the board in a desired pattern. The solder paste is tacky and the components are thereafter placed on the board with their leads extending into the solder paste so that the components are temporarily held in place. The board is then subjected to a process which heats and melts the solder to make the mechanical and electrical connections. In the past, when components were surface mount soldered to a printed circuit board, the electrical connector was subsequently put in position on the board and then a wave soldering step was utilized. This extra step is disadvantageous in that it requires additional time as well as requiring wave soldering equipment. It would be desirable to be able to eliminate this extra step and the wave soldering equipment when electrical components are surface mount soldered to a printed circuit board.
It is therefore an object of the present invention to provide an electrical connector which is amenable to surface mount soldering. Accordingly, connectors then could advantageously be mounted to both sides of a printed circuit board.
In contrast with the wave soldering process, the amount of solder in the surface mount process that can enter a circuit board hole is limited. Accordingly, it is another object of the present invention to provide an electrical connector which can be surface mount soldered to a printed circuit board with a small amount of solder and still maintain a good mechanical and electrical joint.
When surface mounting a connector to a circuit board after the other electrical components have been temporarily adhered to the solder paste, care must be taken to keep vibrations to a minimum so that the electrical components are not displaced. Accordingly, it is another object of this invention to provide contacts extending from the connector which can be inserted into circuit board holes with a low insertion force, provide retention for the connector, and not generate vibration which would displace the other electrical components.